Forum: F-22A Raptor

Elite Joined: Aug 02, 2006 Posts: 819 Status: Offline

Even though it may not be apparent to some people or at first glance, there appears to me a very significant difference in the plan form of the F-22 (and F-35) compared to previous wing-tail designs.

To be specific, let's say that compared to an F-15, F-16, F-18 or any other traditionally laid out aircraft, the F-22's wing is MUCH FURTHER AFT in relation to the location of the engines and the fuselage. If you remove the tail appendages, the F-22 looks all of a sudden like a Mirage or a delta type aircraft with perhaps little more trailing edge forward sweep than usual. The F-35's with its less pronounced leading edge sweep is still nevertheless just as aft winged. The differences in wing placement between the F-22 and F-35 vs say an F-16 is stunning!

In fact, if you align the engine nozzles, you'll notice the the F-22 and F-35 wings are just as far aft as that of the EF Typhoon. If we remove the tails and canards, the Typhoon, F-22 and F-35 look very similar as far as where the wing goes on the aircraft! In this respect, the stealths are more similar to a Typhoon that the F-16 or F-15 for instance. The difference of course is that instead of canards, a set of very large lobster tails (some 3~5 times larger in area than the Typhoon's canards) projects from way aft behind the wing.

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Yes, i noted too this particular since the LM ATF design loose canards, the overall shape substantially is still the same.
The enormous control surfaces and their distance from the body is an important contribute to the exceptional maneuverability of the 22, maybe more than vector-thrust.
As you noted if you imagine to cut them away you still get an A/C like Mirage..

My impression is that the main difference between the F-22/F-35 and all the other planforms is their engines are moved forward toward their centers of gravity. One reason could be to reduce the pitch moment of inertia, for quicker pitch response. Others are to partially hide their exhaust plumes and reduced inlet length (less drag). If you align the planforms (F-22/F-35 vs F-15/F-16/F-18) at the CG, I think you will see what I mean. Comparison with Typhoon, although interesting, is not really valid, since it is a canard delta and all the others are wing/tail. I agree the F-22 looks like a tail-delta. You could compare with the MiG-21, a true tail-delta.

Historically, many early jets (F-80, F-84, F-86) had their engines near the CG, but that resulted in thrust losses in the long, long tailpipe, plus being maintenance nightmares. Even earlier, the Me-262, Gloster Meteor, and P-59 all had under-wing twin engines, The century series (F-100, F-102, F-104, F-105, F-106) had their engines moved as far aft as possible. Note the F-101 is not on that list , due to its forward mounted twin engines, similar to F-4. So it seems we are moving back to the forward mounted engines of 50-60 years ago.

Did you do those graphics DW? They are really good. Thumb

Veteran Joined: Mar 10, 2006 Posts: 329 Status: Offline

i can only see the first one

Elite Joined: Aug 02, 2006 Posts: 819 Status: Offline

sprstdlyscottsmn wrote:

i can only see the first one

It's imageshack. I don't know how they implement their stuff. But my guess is that they do it like every other service that promises a lot of space for "free". Basically, the speed and redundancy required of disk arrays serving data centers means that a lot of times only about 10% of a small number of disks is used a lot and/or contain stuff that matters (or at all). The others are sitting there as backups or with old data that does not get accessed much if at all. In fact, to minimize seek latency and to maximized throughput through load distribution, a lot of times disks are intentionally and drastically under utilized. In many instances, such as with search engines like Google, "hot" disks holding frequently used data and caching invariably become "cold" drive with older data that isn't used much. They also happen to have a lot of unused space which was intentionally unused during their "hot" cycle. These spaces are traditionally simply wasted and left to fallow. But somewhere along the line, people start using them to offer free hosting and massive email accounts and things like that. When the drives become hot again you simply have to wait a long time in the lowest priority queue to be serviced when retriving these non-essential data from them -- you may notice that sometimes a few out of 100 images or videos seem to take minutes to load even though the rest took seconds. That is probably why. Now, your gmail stuff may be backed up a few times over -- albiet again using non-performance garranteed space -- but frequently free image and video hosting services don't even do that. If a drive is pulled or gets reconstructed for corruption, you simply lose your stuff! If the drive is busy doing what matters, you simply wait a long time or simply time out and never get your stuff. To them its not that important, and it shouldn't be to you either or you won't put them on some free service with no performance and reliability garrantee!

Anyway, I re-uploaded them and fixed the links.

Forum: F-22A Raptor

F-22A -- a Delta in disguise?